I have a relatively large tile shower that is leaking very slightly onto the ceiling of the room directly beneath it. My question to the experts is this : "Do all showers (including custom) have a "shower pan" (not sure that is the correct name)?" The reason I am asking is that I have not been thinking that the leak is around the base of the wall where the tiles meet the floor. The reason I was not thinking this is due to the fact that I assumed there was a shower pan and therefore the water could not escape. Is this the case? Should I apply clear silicone over the grout around the base of the shower? Any help will be appreciated greatly. Thanks.

If the shower is against inside walls, cut a hole on the other side of the wall and inspect the board behind the tile from the back. The pans should have a waterproof membrane. Sometimes these things leak for years before it shows up.

Before you cut holes in the wall. Look at the shower first. Check the grout around the shower around floor / walls if grout bad fix with new grout. Check the shower valve face plate. Pull it off and see it the gasket is good some times the water leaks there sometimes. Look at everything first be you start hacking up the walls.

I wouldn't assume there is a pan underneath. If the downstairs ceiling is already damaged, that might be the place to cut a hole and see what you can see. Possibilities include the seal around the drain cup and the plumbing connections in the wall. Is there an access panel for the shower faucet plumbing in the wall behind that area? Could be a dripping shut-off valve.

A close visual inspection of the tile grout should show any cracking substantial enough to cause damage.

Thanks for all the help. I inspected the grout and it was pretty poor. For now I put a like coat of clear silicone over the base grout and it seems to have fixed the problem. Thanks. It is nice to know there is somewhere to go for advice like this.

Don't be surprised if you eventually have to rebuild the shower. Depending on the age of the house, and under what standards the shower was originally constructed. I've had experience with a "leaker," but at least it didn't cost me anything to have the old unit ripped out and redone.

So awhile ago several of you responded to my post about a leaking shower. Well I thought the masterful caulking job I did in the shower solved this problem. Well, not so fast. Today I went to paint the ceiling that was stained. Guess what, I was wet. I never fixed the problem. I was still slowly leaking. I cut a 12"x12" hole in the ceiling and found out where the leak was. The shower rain "flange" (not sure if that is what it is called) had no seal under it and between the shower floor. So, the water was getting under the drain and dripping into the ceiling. I believe I have now really fixed the problem.

I notice that a lot of people don't close out issues and update you guys so I just wanted to let you know where this stood. I should have cut out the ceiling sooner. Oh well. Thanks again for all your input and advice.